It is known, for example in the context of cellular radio telephone systems, for the subscriber number of the telephone from which a call is originated to be transmitted in binary code to the telephone receiving the call. This is known in the art as Calling Line Identification (CLI).
Prior art telephones have been adapted to respond to CLI signals and have been provided with a facility for displaying the telephone numbers of incoming calls. Hence the user can see the telephone number before answering the call and so the user can choose whether or not to answer the call. However, if the user chooses not to answer, the telephone will ring for as long as the caller persists with the call, and of course the caller will be aware that he has established a line and that the call has not been answered. A so-called `call-in-absence` memory has also been provided for storing the telephone numbers of incoming calls which have not been answered within a predetermined period of time. The stored numbers can be recalled at a later time so that the user has a record of calls received but not answered.
GB-A-2014825 discloses a telephone apparatus in which the number of a caller is stored in a memory and can be recalled at a later stage if the call is not answered initially.